The subject invention is directed to a multi-function tool system which allows use of a singular tool housing with a plurality of individual tool head housings having respective tools. In particular, this invention relates to a multi-function tool having an electric motor drive system located within the tool housing and a plurality of individual tool head housings adapted to be mounted on the tool housing. Still further, this invention directs itself to a multi-function tool system wherein a plurality of tool head housings are adapted for interface with a singular tool housing. Still further, this invention directs itself to a multi-function tool system where each tool head housing has contained therein a respective reduction gear in order that one tool housing can be used for a plurality of tool members. Still further, this invention is related to a multi-function tool system having a safety switch which allows the user to deactuate a rotatively displaceable tool. Still further, this invention directs itself to a multi-function tool system where a safety switch mechanism is displaceably mounted on the tool housing and includes an extension or lug member for reversible insertion into a recess or blind hole formed in a tool head housing.